1. Field of the Invention
The present invention relates to a weather strip extrusion into the shape of a long piece whose cross-sectional shape varies along its longitudinal direction, and a method and an apparatus for extrusion-molding the same weather strip.
2. Description of Related Art
It has conventionally been customary to attach a weather strip along the circumferential edge of openings of a motor vehicle body for providing a seal between the car body and mating members such as doors. As shown in FIG. 26, a weather strip 51 comprises extrusion members 52, 53, 54 and 55 formed into the shape of a long piece by extrusion molding and having a uniform cross-sectional shape along the longitudinal direction thereof, respectively, and molded members 56, 57, 58, 59 and 60 (the dotted portions in FIG. 26) formed by means of mold-molding apparatus, such as injection-molding apparatus, so as to be continuously connected to the extrusion members 52 to 55.
The extrusion member 55 of the weather strip 51 comprises a mounting base portion 61 which is to be fixed to the vehicle body and a sealing portion 63 projecting from the mounting base portion 61 and having an inside hollow portion 62 as shown in FIG. 27 (which is a cross-sectional view taken along the line XXVII--XXVII of FIG. 26), for example. When the edge portion of a door glass is brought into contact with the sealing portion 63, a sealing wall 63a of the sealing portion 63 deforms to provide a seal between the sealing portion 63 and the door glass edge portion. A reinforcing bridge portion 64 may be formed in the hollow portion 62 so as to cross inside the hollow portion 62.
By the way, it is necessary for a part of the weather strip 51 which is to be attached to the roof section of the motor vehicle, when the upper edge of the door glass is brought into contact therewith, to wrap up the upper edge of the door glass as reliably as possible. For this purpose, the extrusion member 54 corresponding to the roof section is formed with a concave portion 65 in the sealing wall 63a of the sealing portion 63 as shown in FIG. 28 (which is a cross-sectional view taken along the line XXVIII--XXVIII of FIG. 26). Meanwhile, the extrusion member 55 corresponding to the rear quarter section of the motor vehicle is not required to wrap up the door glass edge so reliably when the rear edge of the door glass is brought into contact therewith, and therefore it is not formed with such concave portion 65 as shown in FIG. 27. Namely, according to the prior art, when forming the extrusion members 54, 55, the members with and without the concave portion 65 are formed separately. Incidentally, in the extrusion member 54 for the roof section, no bridge portion 64 is formed and the thickness of the inner peripheral wall of the hollow sealing portion 63 is partially made thin in order that the extrusion member 54 can be deformed more reliably when wrapping up the upper edge of the door glass.
The cross-sectional shape obtained by the extrusion molding is unchanged at any point of the member along the longitudinal direction. Further, for the cross-sectional shape of the member having the hollow portion, it is difficult to change the cross-sectional shape of the hollow portion. It is therefore necessary that the extrusion members 54, 55 having different cross-sectional shapes agreeable to the purposes for which they are used, are formed separately. Further, in order to obtain these extrusion members 54, 55, it is necessary to use different molding dies. Moreover, it is necessary to mold the molded member 58 for connecting these extrusion members 54, 55. In consequence, the manufacturing operation becomes complicated and equipment such as the molding dies and the molds for each of the members, extruder and mold-molding apparatus are specially required, thus giving rise to a problem that the production cost comes expensive. In addition, many other problems are raised such as that the need for many pieces of equipment causes the need for a large space for the installation of such equipment.
The present invention solves the above problems. An object of the present invention is to provide a weather strip whose cross-sectional shape varies along its longitudinal direction and a method and an apparatus for extrusion-molding the same weather strip by which the manufacturing can be simplified at the time of extrusion-molding and the cost can be reduced. Further, another object of the present invention is to reduce the cost by forming a part of the weather strip which is attached at least from the roof section to the rear quarter section, into a piece of extrusion member whose cross-sectional shape varies along its longitudinal direction.